The Java programming language has been around since 1995 and has been the default language for Android app development since the platform was first introduced back in 2008.

Since then, Java has amassed enormous support and popularity in the dev community. 

Even with the emergence of Kotlin as the new preferred language for Android mobile app development since 2019, Java is still widely used.

In this article, we’ll review why Java is still many developer’s go-to programming language and how it stacks up against other popular languages for Android, like Kotlin.

Table of Contents

1. Java for Programmers
2. Java Features
3. Must-Haves for Java Mobile Development
4. Android Studio
5. NetBeans
6. Gradle
7. Eclipse
8. Oracle JDeveloper
9. Java vs Kotlin
10. Kotlin
11. Extension Functions
12. Null Safe
13. Data Classes
14. Coroutines Support
15. Which is Better?
16. Which Should You Choose?

Chapter #1: Java For Programmers

Java is a class-based, object-oriented programming language that was created to carry as few dependencies as possible so the compiled Java code could run on all Java-supported platforms without the need for recompilation.

In short, it’s always embraced the concept of “write once, run anywhere”.

Java was originally created by Sun Microsystems, which has since become Oracle Corporation. This language uses syntax that comes from other languages like C and C++.

1.1 Java Features

Java has many features that make it a popular choice among both web and mobile app developers.

Let’s take a look at a few.

• Object-oriented: Just like with Python, C++, and Ruby, Java is an object-oriented programming language. Everything is an “object” that contains code and data.
• Platform independent: Since Java programs are first converted to bytecode by the Java compiler, the code can run on any machine that supports the Java runtime environment—making it platform-independent.
• Secure: Since Java is platform independent and has almost no interaction with the operating system, it makes the language much more secure than other programming languages.
• High-performing: While Java is an interpreted language, unlike C or C++ which are compiled, it nonetheless is high performing due to its own just-in-time compiler.
• Multi-threaded: With Java you can write applications that conduct multiple tasks in separate threads. For example, a Java app can serve users a login form while also running background processes. 
• Open-source: Over the years, Java has amassed a great collection of open-source libraries that make java mobile apps much easier to develop.
• Community support: Since Java is an older programming language, it has a large community of developers that share valuable insights and knowledge when it comes to Java app development. 

Chapter #2: Must-Have for Java Mobile Development

As discussed in the previous chapter, one of the greatest benefits to using Java is its wealth of open-source tools and libraries.

Here are some of the most widely used Java tools for building the best Java mobile apps.

2.1 Android Studio

Android Studio is a must for developing Android mobile applications and is the official integrated development environment (IDE) for the Android platform.

Android Studio is based on IntelliJ IDEA, which is a Java-written IDE that’s designed to maximize productivity with its powerful code editor and developer tools.

Some additional features of Android Studio include a fast and feature-rich emulator, a flexible Gradle-based build system, a unified environment for developing apps for Android mobile devices, Lint tools, and so much more.

2.2 NetBeans

Just like Java itself, NetBeans is another product from Oracle Corporation. It’s an IDE designed for the Java language, and is completely free.

Developers can use NetBeans to create not only mobile applications but also desktop and web apps.

NetBeans runs on a modular architecture with a whole host of tools and features for the app development process, from idea inception to app store launch.

It comes with code analyzers, converters, visual debuggers, editors and more that help facilitate the app development cycle.

2.3 Gradle

Gradle is a flexible build automation tool that runs on the Java virtual machine (JVM) and requires a Java development kit.

Developers can use Java APIs in their build logic, like plugins and custom task types, and can use the tool on various platforms.

Since Gradle allows the use of a build cache to reuse task outputs from previous runs as well as other optimizations, it has high performance.

Additionally, most major IDEs like Android Studio and IntelliJ IDEA have the ability to import Gradle builds and interact with them.

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2.4 Eclipse

Eclipse is another popular IDE that provides assistance for code refactoring, syntax checking, and overall, code completion.

It also offers the Java Development Tools project (JDT) which contributes a set of plugins which add the capabilities of a full-fledged Java IDE to the Eclipse platform.

While Eclipse is famous for their Java IDE, they also offer a number of other helpful IDEs, like a C/C++ IDE, JavaScript/TypeScript IDE, PHP IDE and much more.

2.5 Oracle JDeveloper

Oracle JDeveloper is a completely free IDE that simplifies Java-based app development by addressing every step of the application cycle, from modeling and coding, to debugging, monitoring and deployment.

This IDE is optimized for the Oracle platform and assists with hand-coding, Java database connectivity (JBDC) compliance, cross-platform capabilities, testing, debugging and more.

Chapter #3: Java vs Kotlin

As already mentioned earlier, Kotlin has taken Java’s place as Google’s official language for Android app development, but that doesn’t mean developers have abandoned Java.

So which language is better and which should you use for developing mobile apps?

Let’s take a look at how Java and Kotlin stack up against each other and what each brings to the table

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3.1 Kotlin

We’ve already reviewed what Java is and a few of its benefits, but what’s Kotlin?

Kotlin is a free, open-source programming language that runs on the JVM and is the official language of Android development.

Similar to Java, Kotlin can also be used in the same areas, including web, server, client, and Android applications development.

While it’s the youngest programming language out there, it’s proven to be a powerful one with robust features and clean code.

Now let’s dive into some differences between the two languages.

3.2 Extension Functions

For developers who want to extend the functionality of existing classes, with Java, you would need to create a new class with those functionalities that would also inherit from the parent class.

With Kotlin, the language provides the ability to extend existing class functionality simply by prefixing the name of the class to the name of the new function.

3.3 Null Safe

Null safety, also referred to as void safety, guarantees that no object references in object-oriented languages like Java will have void or null values.

In Java, developers can assign null to any variable using NullPointerExceptions (which is a runtime exception in Java), but when trying to access an object reference, the null value would raise a null pointer exceptions, which would then need to be handled by the user.

With Kotlin, all types of variables are non-nullable by default, so you can’t assign null values to them. To give a variable a null value, you would need to make a declaration as follows: 

Val num : Int? = null

3.4 Data Classes

Data classes exist solely to hold data and make that data accessible through the use of getters and setters. Data classes are one of the largest collection points of boilerplate code in many application projects.

When using Java, if you need a class to hold only data, you would need to define a constructor , variables to store the data, getter and setter methods, and some functions like hashcode() and toString().

With Kotlin, if you need classes to hold only data, you can declare a class with the keyword “data” and the compiler will take care of all the heavy-lifting, like all those things you need to define when using Java.

3.5 Coroutines Support

Coroutines are components that generalize subroutines for preemptive multitasking by letting the execution be suspended or resumed. They’re used for implementing cooperative tasks, event loops, exceptions, iterators, pipes, and infinite lists.

When initiating a long-running network or CPU-intensive operation, the corresponding thread will get blocked, since Android is by default single-threaded. 

With Java, you can create many threads in the background, but it can get complicated trying to manage them.

With Kotlin, you can create these multiple threads but with coroutines support, which will stop the execution at a certain point without needing to block any threads. 

3.6 Which is Better?

When it comes to choosing Java or Kotlin, you’ll find that each has their own benefits.

Java works on multiple platforms and on nearly every mobile device. The coding is robust and since it’s object-oriented, it’s easier to create modular apps where you can reuse different parts.

But it has some challenges. The syntax of Java can be somewhat cumbersome and more complicated to use when compared to other languages. There are times when Java causes issues with the Android API design. 

Also, Java requires more code for test-driven development and it has a higher risk of coding errors and bugs.

Some mobile apps using Java are Spotify, Twitter, Cash App, and more.

Kotlin, on the other hand, is faster to compile. It’s lightweight and requires writing less code when compared to Java, which tends to be more verbose.

Since Kotlin compiles the code to a bytecode, it can run in the JVM, and so all Java libraries and frameworks can easily transfer and run in a Kotlin project.

Some challenges of Kotlin is that it’s not as popular since it’s a newer language, so the developer community is much smaller than well-established languages like Java.

Because of this, it also has fewer libraries and tutorials.

PRO TIP:
Kotlin has a steep learning curve and has a syntax that’s fairly different from Java, so going from Java to Kotlin would take time. If your dev team is proficient in Java, don’t expect a quick and easy transition to Kotlin.

Some applications that use Kotlin are Pinterest, Trello, Evernote, and more.

3.7 Which Should You Choose?

As you can see from the previous section, each language has its own pros and cons. 

For a development team that’s proficient in Java, it makes sense to stick with that language, even though Kotlin does have some convenient benefits over it, like null safety, lambda expression, and more.

But if you’re starting a fresh project and looking to hire an app development company, it might make more sense to find developers who can code using Kotlin since it is Google’s official programming language for Android development and comes with a wide breadth of features.

At the end of the day, both languages are robust and powerful and would serve well to develop any kind of Android mobile app.

Final Thoughts

Java is an incredibly powerful and well-established programming language with an enormous community and a wealth of libraries and tools that can help anyone build a mobile app.

It’s easy to learn, has cross-platform capabilities, and it’s secure, making it a language of choice for app development.

If you’re still unsure whether Java is right for your mobile app project, our Simple Starter package includes a full technical write up that includes details like the tech stack you’ll be using for your project, along with wireframes and market research.

What programming languages are you most loyal to and why?